Genomic imprinting Flashcards
What are the two disorders from genomic Imprinting ?
Angleman
Prader-willi
What are the difference between monoallelic and Biallelic mutation ?
Monoallelic - only one allele (heterozygous)
Biallelic - both alleles (Homozygous)
What are the Causes and CF of Paraganglioma
PATERNAL EXPRESSED
TUMOUR IN PARASYMPATHETIC GANGLIA
AD
What are the Causes and CF of Beckwith Wide en Syndrome ?
MATERNAL EXPRESSED
OVERGROWTH
AD
What causes underexpression or overexpression of gene not of a parent specific origin regarding Imprint ?
Defect in Imprinting
Parent origin specific effect is caused by?
Mutation in Imprint
What is Resetting of Imprint ?
After Puberty, Boy will inherit father’s Imprint
Female will inherit mother’s Imprint
What is the gene causing angleman syndrome ?
UBEA-3
Gene causing Prader will syndrome ?
SNRNP
Gene causing Biallelic imprinting syndromes?
OCA2
What are the 4 mechanism of Prader will and Angleman syndrome ?
- Deletion of chromosome 15
- Uniparental isodisomy (Both paternal in Angleman, Both maternal in Prader-willi)
- Loss of function mutation
- Both maternal and paternal are imprinted.
What causes Uniparental Isodisomy ?
Nondisjunction in Miosis 2
Identical chromosomes from same parent
What causes Uniparental Heterodisomy?
Nondisjunction in miosis 1
Different chromosomes from same parent
What causes Uniparental disomy?
Trisomic rescue
Division of trisomic chromosomes leading to 2/3 normal (disomic) chromosomes and 1/3 UPD (tetrasomic) chromosome
How is Both angelman and Prader-willi syndromes detected ?
What is the probe used?
Whats is the Restriction enzyme used?
By southern blotting
Restriction enzyme - NOT-1 (methylation sensitive) will not cut methylated allele
Probe- SNRNP PROBE
IF MATERNAL CUT - ANGLEMAN
IF PATERNAL CUT - PRADERWILLI
Prader-willi symptoms ?
Hypotonic
Hypogonadism
Type 2 DM
HYPOPIGMENT
Intellectual disability
Angleman syndrome symptoms ?
Frequently laughing
Seizure
Ataxia
Absent speech
Slow to gain weight
